The present invention relates to devices for injecting, administering, infusing, dispensing or delivering a substance, and to methods of making and using such devices. More particularly, it relates to a device for administering a fluid or liquid product or substance such as a medicinal or therapeutic substance, and to a method for preparing the device for performing an administration. More particularly, in some embodiments, the present invention relates to a device for administering an active agent from a two-chamber reservoir, wherein the device comprises a controller and/or a control means for controlling the progression for preparing and administering the fluid product.
A multitude of administering devices are known from the prior art, using which a liquid or fluid drug or other fluid product can be administered from a container such as a glass carpoule or ampoule. The product container is inserted into the administering device, wherein a drive member or drive element such as a piston rod is connected to a stopper in the container to move the stopper to administer the product. A movement of the drive member relative to the container of the administering device advances the stopper within the container, such that the drug is delivered through an injection needle connected to the container. The use of such administering apparatus is facilitated by the fact that the devices are intended to be used once, i.e. once a container has been emptied, the administering device together with the container is disposed of. Changing the container is not necessary. It is also common for the length of the advancing movement for delivering the drug to be predetermined by structural measures and to not have to be set by the user. In addition, devices are also known in which a separate venting or priming step is provided, by which a quantity of air which may be situated in the container is removed from the container before the active agent is delivered. Lastly, there are administering devices which are specialized for administering fluid products from two-chamber carpoules or containers. In such two-chamber carpoules, it is necessary to mix the fluid product to be administered shortly before use, since the active agent is, for example, provided in a solid form in a first chamber and a corresponding solvent for the active agent is provided in a second chamber. To mix the fluid product, a fluid connection between the two chambers is established by advancing the stoppers within the carpoule, such that the solvent enters the chamber of the solid active agent. The use of such a two-chamber carpoule and how it is mixed is known from, for example, EP 0 298 067 B1.
A pre-filled syringe is known from EP 0 911 046 B1. The syringe comprises a piston rod comprising a stopping means for mixing a product in a two-chamber container, wherein the progression when mixing the product is controlled by the stopping means. For this purpose, the stopping means projects laterally from the piston rod, such that it abuts against the rim of the container when the piston rod is slid in and stops the movement of the piston rod. The solvent then enters the chamber of the active agent via a bypass, such that the product is mixed. Sliding the piston rod further in folds the stopping means towards the axis of the piston rod and inserts it into a cavity within the piston rod, such that the piston rod can be slid further into the container. Continuing to slide the piston rod in enables the product to be delivered from the container.
A similar device is known from EP 0 793 973 A2. In this double-chamber syringe, the circumference of the piston rod comprises one or more protrusions which briefly interrupt the advancing movement of the piston rod into the syringe container. The interruption serves as an indication that the solvent has entered the active agent chamber via the bypass and the mixing procedure has been completed. Sliding the piston rod further in overcomes the resistance from the protrusions and enables the product to be delivered from the syringe. (The disclosures and teachings of the three EP documents cited herein above are incorporated herein by reference.)